Injection current and infrared photosensitivity in isotype p-PbTe/p-CdTe heterojunctions

Iso-type p-PbTe/p-CdTe heterojunctions were grown on BaF2 substrates by using the hot-wall epitaxy technique. The growth details are presented. The carrier transport mechanism was investigated by means of the current-voltage measurements. At 77 K the dominant conduction mechanism was found to be the space-charge-limited current. The photovoltaic response in the long-wave infrared region with the half-peak cut-off wavelength ranged from 8.0 to 9.0 m was observed in these heterojunctions for the first time. The possible mechanism of the photoresponse is the internal photoemission of holes from p-PbTe across the heterojunction barrier

Theoretical foundations of hot spots policing and crime mapping features

The study is devoted to one of the ways to solve the problem of reducing the crime rate in the region due to the concentration of police forces and means in correctly defined places of criminal activity. The purpose of the study is to determine the content of the concept of police activity in places where criminal activity is concentrated in “hot spots” and examine the features of crime mapping. The key methods used are system and structural analysis, dogmatic analysis, synthesis method, modelling method, and structural-functional and formal-logical methods. It is determined that the problems of criminal activity, for the most part, are concentrated in a small number of places of an administrative- territorial unit, which continue to be dangerous for a long time in the absence of police intervention. It is proved that different types of “hot spots” require the development of individual police countermeasures, and the analysis of “hot spots” should be based on a logical and systematic approach and depends on understanding the theory of the origin of different types of analysed criminal offences and choosing the way to display the results. A reservation is made that arbitrary analysis by an analyst, or the use of only software algorithms is excluded because they can lead to a subjective perception of a “hot spot”, which may not turn out to be an accumulation of criminal activity. It is proved that the analysis of “hot spots” , in addition to simply identifying places with high crime rates, is crucial for solving problems in these places and choosing the most effective police response measures. The practical value of the proposed study is to generalise and adapt international developments to improve the theoretical and practical foundations for improving the efficiency of criminal analysis units of the National Police of Ukraine in the field of visualisation of information about criminal activity, introducing international experience in crime mapping into the practical activities of criminal analysis units of the National Police of Ukrain